Packing



May 12, 1942.

J H. HALSTEAD PACKING Filed June 24, 1940 2 Sheets-Sheet 1 INVENTOR.g/OHN f2. 1554 L8 TEA a BY 'M g? e% I ATTORNEYS.

J. H. HALSTEAD PACKING May 12, 1942. 2,282,312

2 Sheets-Sheet 2 Filed June 24, 1940' INVENTOR. /8 Jaw/v H HALSTEAD M?TTORNEYS.

Patented May 12, 1942 UNITED STATES PATENT OFFICE PACKING John H.Halstead, San Jose, Calif. Application June 24,1940, Serial No. 342,106

' 2 Claims. (01. 286-26) My invention relates to packing, and moreparticularly to packing ring to'be used between relatively movingconcentric cylindrical parts, such as, for example, pistons operating incylinders.

Among the objects of my invention are: To provide a packing having awide bearing surface on a moving part; to provide a packing operatingunder compression; to providea means and method of packing a piston withthe material under pressure varying throughout the packing contact; toprovide a simple and efficient packing annulus; and to provide a packingannulus wherein pressure is automatically maintained against a movingpart on the pressure side of the packing.

Myinvention possesses numerous other objects and features of advantage,some of which, together with the foregoing, will be set forth in thefollowing description of specific apparatus embodying and utilizing mynovel method. It is therefore to be understood that my method isapplicable to other apparatus, and that I do not limit myself, in anyway, to the apparatus of the present application, as I may adopt variousother apparatus embodiments, utilizing the method, within the scope ofthe appended claims.

In the drawings:

Fig. 1 is a view, partly in section and partly in elevation, of myinvention as applied to a hydraulic device, such as a hydraulic ram orlift.

Fig. 2 is a plan view of a packing annulus used in Fig. 1. 4

Fig. 3 is a cross sectional view taken as indicated by the line 3-3 inFig. 2.

Fig. 4 is the diagram showing how the packing annulus is applied to thepiston of Fig. l.

Fig. 5 is a cross sectional view of a packing annulus having aperipheral bearing surface.

Fig. 6 is a cross sectional view of a piston utilizing double packingfor adouble action piston seal.

Fig. 7 is a plan view of the packing annulus utilized in Figs. 6 and 7.

Fig. 8 is a cross sectional view of the packing annulus taken asindicated by the line 88 in Fig. 7.

Referring directly to the figures for a more detailed description of myinvention and the advantages thereof, and first to Fig. 1, whichillustrates a hydraulic ram or lift, a cylinder I, which may bestationary, is provided with a closed bottom 2 and an open top 3.Positioned within cylinder I is lift piston 4, which may be hollow orsolid as desired. Near the top of cylinder I is positioned a guidebearing 5, and

.plan view in Fig. 2 and in cross section in Fig. 3. I

The packing annulus 1 is preferably formed of multiple layers of fabricimpregnated with rubber or the like, the fabric planes extendingparallel to the planar surfaces of the annulus. The packing annulus usedin the device of Fig. 1 has an interior aperture II), the edges of thisaperture being provided with a beveled surface H. The annulus I is alsoprovided with bolt apertures 12 so that the outer portion of the annulusmay be bolted firmly against shoulder 6 by the use of an annularretaining plate [4 and bolts I5 passing through apertures [2.

The fluid for raising piston 4 may be supplied by an inlet pipe l6 intocommunication with cylinder space H, as is well known in the art.

The interior bevel II has a dimensional relationship with piston 4 inthat the greatest diameter l8 of aperture I0 is a diameter registeringclosely with the diameter of cylinder 4, whereas the lesser diameter I9of the aperture In is smaller than the piston 4. However, the. packingannulus 1 maybe easily applied to cylinder 4 by coning the annulus, asshown in Fig. 4, so that the bevel edge ll exactly fits thecircumference of piston 4 on both diameters. In this position, thepacking annulus is easily forced over the cylindrical surface of piston4 until. the advancing surface of the annulus contacts shoulder 6.Retaining plate I4 is then placed over the packing annulus and thepacking annulus is then flattened by pressure applied by bolts l5. Thus,the smaller diameter [9 of the packing annulus aperture becomescompressed and forms protuberant shoulder 20 around the piston 4, thisshoulder extending in the direction of the cylinder pressure. The outeredge of the aperture I0 is under practically no pressure against thecylinder, and the pressure gradually increases toward the inner surfaceof the packing annulus, the inner edge of the annulus providing thetightest seal.

It should also be noticed that I may provide a small space 2| betweenbearing 5 and piston 4 so that cylinder pressure may reach the shoulder20 to force the material thereof against the cylinder. Thus, there aretwo pressures operating on the sealing edge of aperture [0, namely, thatof the pressure of the distorted packing ring material, and the fluidpressure operating against the protuberant-shoulder 20. i I

It will be seen, therefore, that I have provided a simple, singlepacking element with a beveled surface which forms a fluid-tight sealbetween the cylinder and the piston, and which can be readily andinexpensively manufactured. Furthermore, due to the fact thatv thepacking annulus can be coned to make both diameters of the bevel fit thecylinder at the time of application, the packing is easily applied to acylindrical member.

In Figs. ,5, 6, 7, and'8, I have shown the packing annulus of myinvention provided with bevel II on the exterior of the annulus. In Fig.5, the cylinder I is provided with an interior piston rod 30, thispiston rod being threaded and weldis then placedover the conedpackingannulus and by means of pressure of bolts I forced back 'to-planar'shapeh Thisprovides an outer protuberant shoulder .Zllyiacing :the interiorH of the cylinder, wherein the pressure exists. Inasmuch as piston head3! is made of lesser :diameter than the interiorof cylinder, pressure inthe cylindrical space I] is able to act against teri or cylinder walls;In this case retaining'ring 14 may be used to positionthe pistoncentrally.

In Fig. 6, I have shown a double action piston wherein cylinder 1 isprovided with a central pistonrod 30 anda pistonhead 3l, theonlydifierence being that'in this case the pressure is applied tointeriorcylinder spacel'l at one side of the piston head andto the oppositespace H on'the other side of the,pis ton head. I utilize here twopacking annuli'! and two annular plates l4, withbolts-l5 thatpas'sthrough both plates [4, both packing annuli 11, and piston head 3|. Inthis case, 'I may prefer to provide shoulders; on the annular 'plateslll ratherthan o'n-piston head 3l,".but this isnot important. .In thiscase, however, the piston head 13] Ymayextendclose to theinteriorcylinder walls for positioning, whereas the. annularplates .I4Iare spaced away from the cylinder walls to allow the .press ure inspaces I! and T H to be applied directly Yaga instthe protuberantshoulders '201on eachpa'ckin g annulus. In this case, aslinthe others,each packing annulus'is applied to the interior cylinder walls conedshape and then forced back to generally planar shape'by application ofthe plates I4 un- 'der control of bolts [5,

Thus, it will be seen that Ihave provided a simple packing annuluswherein advantage is gained by the use] of a beveled bearing surfacewhich is readily applied to a cylindrical member by coning theannulusgand'thereafter bringing the packing annulus back to planarshape, thus distorting the material on the smaller diameter of thebevel, forming a lprotuberant portion against which the interiorpressure of the-cylinder may act to better the seal. j

It should also be noted that while I prefer to utilize rubberimpregnated fabricfonthe material of the packing annulus, I wish itto-be distinctly understood thatthe: term rubber in eludes natural,artificial, or synthetic products having-the general characteristics ofnatural rubber. Some of the syntheticqproducts,for-example, have a muchgreater resistance to oil corrosion than does natural rubber andtherefore I do not wish to be limited with respect to the use of naturalmaterial. I have found, however, that certain types of rubber which areacted upon by oil, will, when used in contact with oil actually absorboil, or be other-wise affected by the oil, so that the material swellsonthe pressure side of the packing. Such swelling of the rubber componentvof the packing is in some cases an advantage, in that the swellingautomatically takes up wear and continues, during service, to provide atight seal on the pressure side protubera nt ring to force'it againstthe inp of the annulus.

It should also be noticed that while metal to 1 metal bearing of thepistons in the cylinder does packing; annulusin conical form andthereafter change its shape; Sucha packingannuluswill have a shape asshown-in Fig. 4 on or off 'the piston, Therefore, when the retainingplates-l4 areapplied, distortion will occur inexactly the samemanner,and giving exactly the same re- .sultsas the flatmodification shown inFig. 3/ Furthermore, it will be noticed that while I have shownshoulder-'6 extended relativelyclose to the bevelled edge, I wish itdistinctly understood that'the amount of bearing of the shoulder tonvthesurfaces of the annulus may be varied within wide limitshTheclamping may .in fact, be so near the periphery of .theannulus inthe-device shown in Fig. 3, orsimilarly, so near theinner edge ofaperture 19in Fig. 7, that the portion, of the annulus adjacent thesealing edge I I may still remain in coned shape.

In other words I mayprefernot tocompletely distort the coned ring into aplanar ring. I may utilize the stabilizing clamp at a distance away fromthe sealing edge in orderthat varying degrees of distortion maybeexerted against the sealing edge subjected to cylinder pressure. Thus,in the embodiment shown-in Fig. .4 the clamping may be confined to theextreme periphery of the annulus. This will throw the smaller diameteredge I 9 against piston 4 but the central portionof the annuluswillstill remain conical,,and,there willbe a lesser shoulder ZIi-than ifthe conical shape were entirely reduced to'a uniform plane. Thus onlyapart of the annulus need be flattened to form a properseal. s

I claim:

cylindrical piston member and a cylinder member assembly consisting of*a shoulder phone of said members extending closely'adjacentrand spacedfrom the bearing surface onthehother membensaid shoulder-having anannularc'hannel therein open to said bearing surface, asing'le normallyplanar packing sheet "having an aperture therein, said aperture havingone edge diameter fitting said bearing surface z'and'the other edgediameter smaller thanthe diameter of saidbearing surface,'both of saidedges fitting said bearing surface when: said packing sheet-istemporarily coned with said smaller diameter adjacentsaid channel withthe contiguous surface in contactwith": the remainder er can 1. Meansfor packing; a -relatively movable shoulder, and an annular retainingring bolted to said shoulder and in contact with the surface of saidsheet contiguous to the larger diameter edge thereof for forcing saidconed sheet back to planar shape whereby all of said sheet is planarexcept a distorted portion adjacent said smaller diameter edge, saiddistorted portion being free in said channel.

2. Apparatus in accordance with claim 1 wherein said annular retainingring extends closely adjacent and spaced from said bearing surface andterminates in contact with said sheet adjacent the larger diameter edgeof said aperture.

JOHN H. HALSTEAD.

